The research described in this application is directed toward the establishment of artificial breeding in chimpanzees as a routine method of enhancing the size and quality of the chimpanzee population available to the research community, and to elucidation of reasons for the apparent subfertility of a portion of the captive female population. Specifically we shall undertake the insemination of a number of breeding females with semen from males whose incompetent reproductive behavior presently excludes them from the genetic pool of the colony. We will use laparoscopy, radiotelemetry (of basal body temperature) and raidoimmunoassay of steroid and gonadotropic hormones to investigate the periovulatory events in females who have apparently normal menstrual cycles, but no history fo successful pregnancy. Multiple inseminations will also be performed in these females. In addition we shall investigate the possible role of altered prolactin levels associated with chronic stress situations (close caging, experimental manipulation, etc) on reduction of fertility. Finally we intend to further develop the methodology of rectal probe electroejaculation for use in primate species. The results of this research will provide valuable information for the development of self-sufficient breeding colonies of great apes, and will provide information on a poorly understood area of infertility which will have application to both apes and man.